Researchers tested 134 dead black vultures collected in 2022 and 2023 from seven states. More than 84% of the birds were positive for highly pathogenic avian influenza, H5N1. Lead author Nicole Nemeth of UGA's Southeastern Cooperative Wildlife Disease Study says the tested carcasses "may represent tens or hundreds of thousands of black vultures." The team warns the virus may be having a large, unseen impact on the species.
The study notes that black vultures' scavenging behaviour helps keep the virus circulating beyond the normal bird flu season. Year‑round transmission increases the number of times the virus can copy itself and change, which raises the chance of harmful mutations. The authors say there is currently no evidence that such changes are happening in the vulture population, but the possibility is not known.
Previous work suggests about half of infected vultures survive and survivors show antibodies. Coauthor David Stallknecht says the virus is very transmissible in vulture populations but some individuals do survive. The study also highlights risks for rarer birds: a 2023 outbreak in California condors killed at least 20 birds, and there are fewer than 600 condors overall.
Difficult words
- carcass — the dead body of an animalcarcasses
- scavenging behaviour — feeding on dead animals or animal remains
- transmission — the process of a disease spreading between animals
- mutation — a small change in a virus or organismmutations
- antibody — a protein the body makes to fight infectionantibodies
- transmissible — able to pass from one animal to another
- outbreak — a sudden and large appearance of disease
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Discussion questions
- How could year-round transmission in vultures affect other birds in a region?
- What actions might help protect rare birds like California condors from such outbreaks?
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